An existing multidepartmental, interdisciplinary program of research projects and core facilities focusing on gonadotropins in reproductive biology will be brought together as a Specialized Population Research Center. The Center will involve the efforts of 15 faculty members associated with 10 departments in the University: Anatomy, Biological Chemistry, Biological Sciences, Internal Medicine, Obstetrics and Gynecology, Oral Biology, Pathology, Pediatrics, Pharmacology, and Physiology. The approaches involved range from cellular and molecular to physiological and clinical, with extensive integration of the various levels. Animal models include rats, hamsters, rabbits, sheep, monkeys and human beings. Major research emphasis will be placed on the following problem areas: role olfactory pathways in reproductive behavior; role of gonadotropins in regulation of ovarian cyclicity; localization, regulation, function and action of gonadotropin releasing hormone; inhibitors and steroidogenesis; estrogen action in corpora lutea; gonadotropin action in testes; and molecular and cellular mechanisms and consequences of gonadotropin action in the ovary, including the regulation of follicular development.